<template>
  <div id="home" class="wrapper">
    <nav-bar class="home-nav"><div slot="center">购物街</div></nav-bar>
    <tab-control :titles="['流行','新款','精选']"
      @tabClick="tabClick"
      ref="tabControl1"
      class="tab-control"
      v-show="isTabFixed"></tab-control>
    <scroll class="content"  
      ref="scroll" 
      :probe-type="3" 
      @scroll="contentScroll"
      :pull-up-load="true"
      @pullingUp="loadMore"> 
      <home-swiper :banners="banners" @swiperImageLoad="swiperImageLoad"></home-swiper>
      <recommend-view :recommends="recommends"></recommend-view>
      <feature-view></feature-view>
      <tab-control :titles="['流行','新款','精选']"
      @tabClick="tabClick"
      ref="tabControl2"></tab-control>
      <good-list :goods="showGoods"></good-list>
    </scroll>
    <back-top @click.native="backClick" v-show="isShowBackTop"></back-top>
  </div>
</template>

<script>

  import HomeSwiper from './childComps/HomeSwiper'
  import RecommendView from './childComps/RecommendView'
  import FeatureView from './childComps/FeatureView'

  import NavBar from 'components/common/navbar/NavBar'
  import TabControl from 'components/content/tabControl/TabControl'
  import GoodList from 'components/content/goods/GoodsList'
  import Scroll from 'components/common/scroll/Scroll';
  import BackTop from 'components/content/backTop/BackTop'

  import {getHomeMultidata,getHomeGoods} from 'network/home'
  import {debounce} from 'components/common/utils'
  


  export default {
    name: "Home",
    components:{
      HomeSwiper,
      RecommendView,
      FeatureView,
      NavBar,
      TabControl,
      GoodList,
      Scroll,
      BackTop
    },
    data(){
      return {
        banners:[],
        recommends:[],
        goods:{
          'pop':{page:0,list:[]},
          'new':{page:0,list:[]},
          'sell':{page:0,list:[]},
        },
        currentType: 'pop',
        isShowBackTop: false,
        tabOffsetTop: 543,
        isTabFixed:false,
        saveY:0
      }
    },
    computed:{
      showGoods(){
        return this.goods[this.currentType].list
      }
    },
    destroyed(){
      console.log('home destroyed')
    },
    activated(){
      this.$refs.scroll.refresh()
      this.$refs.scroll.scrollTo(0,this.saveY,0)
      
    },
    deactivated(){
      this.saveY = this.$refs.scroll.getScrollY()
    },
    created(){
      // 1.请求多个数据
      this.getHomeMultidata()

      // 2.请求商品数据
      this.getHomeGoods('pop')
      this.getHomeGoods('new')
      this.getHomeGoods('sell')
    },
    mounted(){
      // 1.图片加载完成的事件监听
      const refresh = debounce(this.$refs.scroll.refresh,50)
      this.$bus.$on('itemImageLoad',() => {
        refresh()
      })
    },
    methods:{
      // 事件监听相关方法
      // 防抖
      debounce(func,delay){
        let timer = null;
        return function(...args){
          if(timer) clearTimeout(timer)
          timer = setTimeout(() => {
            func.apply(this,args)
          }, delay);
        }
      },
      tabClick(index){
        switch(index){
          case 0:
            this.currentType = 'pop'
            break
          case 1:
            this.currentType = 'new'
            break
          case 2:
            this.currentType = 'sell'
            break
        }
        this.$refs.tabControl1.currentIndex = index;
        this.$refs.tabControl2.currentIndex = index;
      },
      backClick(){
        this.$refs.scroll.scrollTo(0,0)
      },
      contentScroll(position) {
        // 1.判断BackTop是否显示
        this.isShowBackTop = (-position.y) > 1000

        // 2.决定tabControl是否吸顶(position:fixed)
        this.isTabFixed = (-position.y) > this.tabOffsetTop
      },
      loadMore(){
        this.getHomeGoods(this.currentType)
      },
      swiperImageLoad(){
        this.tabOffsetTop = this.$refs.tabControl2.$el.offsetTop
      },
      // 网络请求相关方法
      getHomeMultidata(){
        getHomeMultidata().then(res => {
          this.banners = res.data.banner.list;
          this.recommends = res.data.recommend.list
        })
      },
      getHomeGoods(type){
        const page = this.goods[type].page + 1
        getHomeGoods(type,page).then(res => {
          this.goods[type].list.push(...res.data.list);
          this.goods[type].page += 1;

          // 完成上拉加载更多
          this.$refs.scroll.finishPullUp()
        })
      }
    }
  }
</script>

<style scoped>
#home{
  height: 100vh;
  /* padding-top: 44px; */
  position: relative;
}
.home-nav{
  background-color: var(--color-tint);
  color: #fff;

  /* 在使用浏览器原生滚动时，为了让导航不跟随一起滚动 */
  /* position: fixed;
  left: 0;
  right: 0;
  top: 0;
  z-index: 9; */
}
.content{
  /* height: 300px; */
  overflow: hidden;
  position: absolute;
  top: 44px;
  bottom: 49px;
  left: 0;
  right: 0;
}
.tab-control{
  position: relative;
  z-index: 9;
}
/* .content{
  height: calc(100% - 93px);
  overflow: hidden;
  margin-top: 51px;
} */
</style>
